Confidential information is sensitive information regarding, for example, an individual's health or lifestyle that the individual does not wish others to know. For example, biological information regarding an individual is the confidential information. Therefore, for example, in the case where anonymous information including confidential information such as the confidential information mentioned above has leaked from a server that stores the anonymous information in association with personal information, the social life of that individual may be grossly adversely affected. In light of the above, technology for managing the anonymous information in a state in which the anonymous information is separated from the personal information has been developed in recent years.
For example, in Patent Literature 1 described below, there is disclosed a technology for separating a server that stores personal information and a server that stores anonymous information from one another, to thereby provide a user with a service related to the anonymous information (hereinafter referred to as “anonymous service”), while also managing the anonymous information and the personal information separately from one another.